Assume that there is a 015 probabilitythat a sports playoff

Assume that there is a 0.15 probabilitythat a sports playoff series will last four games a 0.30 probability that it will last five games, a 0.25 probability that it will last six games, and a 0.30 probability that it will last seven games. Is it unusual for a team to win in a series of 7games?

Solution

It is not unsual because the tail probability is 0.3, which is not less than 0.05 (general criteria for \"unusal\" is tail probability less than 0.05)